Ls1 pcm bcm tcm
Depending on market and model the PCM holds all the Trans calibrations in one "box."
From 2005/2006 GM started to use two seperate modules PCM & TCM and things got more complicated! (not as user-friendly to tune and play with).
Whether an M6 or A4 the PCM is identical for both types of car. Just tune parameters inside different and of course A4 cals of PCM functional.
BCM is a stand-alone module somewhere in the car (depending on model) and controls all sorts of functions. I don't have a list but things like power windows, central locking, dash control, etc.


